The combined development of networks, wireless communication means, terminals equipped with display screens and interface systems enabling these means to work together, provides users with the possibility of choosing and exchanging digital images through a network such as for example the internet. The screens of these terminals, and especially the screens of portable terminals, do not always have sufficient capacity to display directly an image with relatively high definition, given the number of displayable colors (for screens displaying colors) and the too restricted number of display pixels. “Low” display capacities are for example in the order of 96 by 44 pixels (NOKIA cell phone), 160 by 160 pixels (PALM Personal Digital Assistant). Consequently, the retrieved image, displayed for example on a cell phone screen, is often hardly, or even not, useable visually. All the more so, part of the image constituting a special area of interest of the whole image displayed on the cell phone screen, is even less useable visually by a user of the telephone. Therefore it is of interest for the user to be able to view in good conditions all the special areas, or the subjects of interest of an original image.
Therefore, in order to visually use an image on terminal screens with low display capacity, the image rendering needs to be improved, i.e. obtain the best possible quality of retrieval, given the fact that these devices offer poor display capacities. This improvement of the plotting can be provided by manually cutting out the subject of interest in the original digital image; but this technique has the major disadvantage of requiring prior knowledge of the shape factor of the display of the terminal with low display capacity used to view the image. An automatic means, independent of the terminal with low display capacity used, is thus desirable to determine and display the subject of interest.